Aerospace balloon system and method of operation

ABSTRACT

A balloon system, preferably including a balloon and a payload. A balloon, preferably including a plurality of gores, a plurality of load members, and an apex fitting. A method of balloon system operation, preferably including deflating a balloon, and optionally including operating the balloon system in flight and/or landing the balloon system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 62/969,447, filed on 3 Feb. 2020, which is incorporated in itsentirety by this reference.

TECHNICAL FIELD

This invention relates generally to the aerospace vehicle field, andmore specifically to a new and useful aerospace balloon system andmethod of operation.

BACKGROUND

Stratospheric balloons are typically deflated rapidly from a state inwhich they are substantially fully inflated. However, such deflationtypically must be performed at high altitude (e.g., close to the maximumaltitude reached by the balloon during flight), as higher atmosphericpressures at lower altitudes will typically act to partially deflateballoons. Thus, there is a need in the aerospace vehicle field to createa new and useful aerospace balloon system and method of operation.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a schematic representation of an embodiment of a balloonsystem.

FIG. 1B is a side view of an example of the balloon system.

FIG. 2A is a side view of a balloon of the example depicted in FIG. 1B.

FIG. 2B is a detail view of a portion of FIG. 2A.

FIG. 3 is a perspective view of a portion of a specific example of theballoon.

FIG. 4A is a top view of an example of an apex fitting of the balloonsystem.

FIGS. 4B-4C are top views of a portion of a first and second example,respectively, of the balloon.

FIG. 5 is a schematic representation of cut locations in a portion of athird example of the balloon.

FIG. 6 is a schematic representation of an embodiment of a method ofballoon system operation.

FIG. 7 is a schematic representation of an example of the method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiments of the inventionis not intended to limit the invention to these preferred embodiments,but rather to enable any person skilled in the art to make and use thisinvention.

1. Overview

A balloon system 100 preferably includes a balloon 101 and a payload102, and can optionally include a safety module 103 (e.g., as shown inFIGS. 1A-1B). However, the balloon system 100 can additionally oralternatively include any other suitable elements in any suitablearrangement. A method 200 of balloon system operation preferablyincludes deflating a balloon S230, and can optionally include operatinga balloon system in flight S210 and/or landing the balloon system S220(e.g., as shown in FIGS. 6-7). However, the method 200 can additionallyor alternatively include any other suitable elements performed in anysuitable manner.

2. Benefits

Embodiments of the balloon system 100 and/or method 200 can confer oneor more benefits. In some embodiments, the system and/or method canenable safe and/or rapid balloon deflation (e.g., deflation of partiallyinflated balloons at low altitudes, such as at or near ground level).First, in some embodiments, the system and/or method can reduce thelikelihood of deleterious and/or dangerous interactions between portionsof the balloon after deflation has been initiated. In typical balloonsystems, deflation of some balloons (e.g., partially inflated balloonsat low altitudes) can be subject to interactions such as folding and/orcreasing (which can slow and/or prevent the venting of lift gasescontained within the balloon, and/or can allow air to enter the balloon,where it may mix with the lift gases contained therein). Further, somesuch systems can be subject to interactions such as flapping and/orrubbing (e.g., which can cause electric charge buildup, potentiallyresulting in phenomena such as arcing, which may have the capacity toignite lift gases in and/or near the balloon). Accordingly, it can bebeneficial to reduce the likelihood of such interactions (and/or anyother potentially negative interactions). Embodiments of the systemand/or method can ensure rapid venting of the lift gas (e.g., therebydiluting a flammable lift gas, such as hydrogen, to a safe concentrationat which explosion is unlikely or impossible). However, the systemand/or method can additionally or alternatively confer any othersuitable benefits.

3. Balloon System

The balloon system 100 is preferably a balloon-based aerospace vehicle(e.g., balloon-propelled space capsule), such as a balloon-propelledvehicle configured to operate in the troposphere, stratosphere, and/orany other suitable atmospheric layers. However, the system canadditionally or alternatively be any other suitable lighter-than-airvehicle or aerostat (e.g., airship), space vehicle (e.g., spacecraftand/or space capsule, such as a rocket-propelled space vehicle),aerodyne (e.g., fixed- and/or rotary-wing aircraft), any other suitableaerospace vehicle, and/or any other suitable system configured tooperate in a low- or no-pressure environment (e.g., low-pressure ascompared with human-survivable pressures, such as environments at highaltitude, in outer space, on or near extraterrestrial planetary surfacesand/or surfaces of other celestial bodies such as Mars or the Moon,etc.). In alternate embodiments, the system can additionally oralternatively function as a terrestrial vehicle, a watercraft, and/orany other suitable vehicle.

The system 100 can optionally include one or more elements such asdescribed in U.S. Provisional Patent Application 62/969,447, filed 3Feb. 2020 and titled “Space Capsule”, which is herein incorporated inits entirety by this reference. In examples, the balloon 101 can includeone or more elements described in U.S. Provisional Patent Application62/969,447 regarding the ‘Balloon System’, the payload 102 can includeone or more elements described in U.S. Provisional Patent Application62/969,447 regarding the ‘Capsule System’ and/or ‘Avionics and Power’,and/or the safety module 103 can include one or more elements describedin U.S. Provisional Patent Application 62/969,447 regarding the ‘BackupDescent System’. However, the system 100 can additionally oralternatively include any other suitable elements described in U.S.Provisional Patent Application 62/969,447.

3.1 Balloon

The balloon 101 preferably includes an envelope 110 and an apex fitting120, and can optionally include a nadir fitting 130 and/or any othersuitable elements (e.g., as shown in FIG. 2A). The balloon 101preferably defines an apex and a nadir. When inflated and in flight, theapex is arranged at (or substantially at) the top of the balloon (e.g.,with respect to a gravity vector), and the nadir is arranged at (orsubstantially at) the bottom of the balloon (e.g., opposing the apexacross the balloon along or substantially along the gravity vector). Theballoon can be a zero-pressure balloon, a super-pressure balloon, and/orany other suitable type of balloon.

3.1.1 Envelope

The envelope 110 preferably functions to contain a lighter-than-airfluid (e.g., lift gas, such as helium, molecular hydrogen, etc.). Theenvelope preferably contains enough fluid to fully or substantiallyfully inflate the balloon while it is operating at or near the maximumaltitude of a flight. Further, the envelope 110 preferably functions toisolate this lighter-than-air fluid from the surrounding atmosphere(e.g., preventing mixing of oxygen-containing air with the fluidcontained within the envelope).

In some embodiments, the balloon will typically be partially deflated atlower altitudes, due to the significantly increased atmospheric pressureat lower altitudes. For example, if the balloon is a zero-pressureballoon (e.g., in which the lighter-than-air fluid is at substantiallythe same pressure as the atmosphere surrounding the balloon), then theballoon will typically be partially inflated substantially in proportionto a pressure ratio between the lowest atmospheric pressure encounteredduring flight (e.g., at the highest altitude attained during flight), oralternatively, an atmospheric pressure at which the balloon will befully inflated, divided by the present atmospheric pressure at theballoon (e.g., at the balloon's current altitude). For example, if theatmospheric pressure at the balloon's highest altitude (at which theballoon was fully inflated) is 1/20 that of the atmospheric pressure atthe balloon's current altitude, then at the current altitude, theballoon will typically be approximately 1/20=5% inflated. In examples,the balloon volume ratio (e.g., current balloon volume divided by volumeof the fully-inflated balloon) and/or pressure ratio (e.g., lowestatmospheric pressure exerted on the balloon divided by the currentatmospheric pressure) can be less than 1%, 2%, 3%, 5%, 10%, 15%, 20%,30%, 0.1-1%, 1-2%, 2-5%, 5-10%, 10-20%, 20-30%, 30-50%, or greater than50%.

The envelope 110 preferably includes one or more gores 111 and loadmembers 112, and can optionally include one or more reinforcementelements 113 (e.g., as shown in FIGS. 2B and/or 3).

The gores 111 preferably define the majority of the surface of theenvelope 110. Each gore is preferably an elongated element defining anapex end and a nadir end opposing the apex end along the length of thegore. Each gore preferably runs substantially the entire length of ahalf meridian of the envelope (e.g., from apex to nadir) but canalternatively have any other suitable length and/or arrangement. Thegores preferably include (e.g., are made of) a polymer film (e.g.,polyethylene) but can additionally or alternatively include any otherlightweight materials and/or any other suitable materials.

The load members 112 preferably function to mechanically connect thegores along their length (e.g., from apex end to nadir end), morepreferably sealing the seam between adjacent gores along its length. Theload members 112 can additionally or alternatively function to carrymechanical loads (e.g., tensile loads) in the balloon, such as loadsbetween the apex fitting 120 and nadir (e.g., nadir fitting 130). Eachload member can define an apex end and a nadir end opposing the apex endalong the length of the load member. The load members preferably includeload tape, but can additionally or alternatively include any elementscapable of sealing the envelope between the gores and/or carryingtensile loads (e.g., meridional tension). However, the load members 112can additionally or alternatively include any other suitable elements inany suitable arrangement.

The reinforcement elements 113 are preferably arranged at and/or nearthe envelope boundaries (e.g., where the envelope meets and/or attachesto fittings, such as the apex fitting 120 and/or nadir fitting 130). Forexample, the envelope can include one or more reinforcement elementsarranged around the border of the apex fitting, such as where theenvelope attaches to the fitting (e.g., wherein the fitting attaches tothe reinforcement elements). These reinforcement elements can includeadditional load tape, balloon materials such as the materials includingthe gores, and/or any other suitable materials.

However, the envelope 110 can additionally or alternatively include anyother suitable elements in any suitable arrangement, and/or canalternatively be of unitary construction (e.g., made of a single pieceof material, such as a polymer film).

3.1.2 Apex Fitting

The apex fitting 120 preferably functions to mechanically couple (e.g.,connect) elements of the envelope (e.g., load members, gores,reinforcement elements, etc.) at or near the balloon apex. The apexfitting can further function to controllably decouple elements of theenvelope from each other (e.g., to initiate balloon deflation). The apexfitting is preferably arranged at and/or near the balloon apex (e.g., atan aperture defined in the envelope 110 around the balloon apex), butcan additionally or alternatively have any other suitable arrangement.

The apex fitting 120 is preferably configured to attach to the envelopeno, such as by mechanically coupling to elements of the envelope (e.g.,elements such as gores, load members, and/or reinforcement elements,etc.). In examples, the apex fitting can clamp onto envelope elements,be adhered to envelope elements, be mechanically coupled to envelopeelements by friction, be attached to envelope elements by ties and/orfasteners, and/or mechanically couple to elements of the envelope in anyother suitable manner. In one example (e.g., as shown in FIGS. 4A-4C),elements of the envelope (e.g., load members 112) are clamped betweenconcentric rings of the apex fitting. The apex fitting preferably formsa seal with the envelope (e.g., wherein the apex fitting fits into andseals an aperture in the envelope), but can alternatively couple to theenvelope in any other suitable manner.

The apex fitting 120 is preferably configured to hold one or moreelements (e.g., load members) of the balloon in tension (e.g., whenconfigured in a first mode). When substantial tensile loads (e.g.,meridional tension) exists in the balloon, these loads are preferablycarried by the load members (but can additionally or alternatively becarried by the gores and/or any other suitable elements of the balloon).These loads can arise due to forces exerted on the envelope by retaininglift gas (e.g., when inflated), due to supporting a payload (e.g.,payload carried by the balloon, such as tethered to the balloon nadir),and/or arising from any other suitable forces exerted on the balloon.The apex fitting preferably retains the load member apex ends at or nearthe balloon apex, accepting tensile loads from the load members andthereby holding the load members in tension when such tensile loadsexist.

The apex fitting is preferably configured to split apart the balloon ator near the apex (e.g., when transitioning from the first mode to asecond mode). Different portions of the balloon are preferably attachedseparately to the apex fitting (e.g., attached to separate portions ofthe apex fitting). These balloon portions can include subsets (e.g.,contiguous subsets) of envelope elements (e.g., gores, load members,reinforcement elements, etc.), such as shown by way of examples in FIGS.4B and/or 4C. The apex fitting is preferably attached separately to aplurality of balloon portions, preferably two balloon portions butalternatively more than two (e.g., 3, 4, 6, 8, 5-10, or more than 10portions).

The apex fitting is preferably operable to separate (e.g., mechanicallydecouple) the different balloon portions from each other. In a firstexample, this decoupling can be achieved by splitting the apex fittinginto multiple pieces (e.g., each connected to a different balloonportion), such as by mechanically decoupling the pieces of the apexfitting from each other (e.g., wherein the tensile load pulls apart themultiple pieces in response to the decoupling). In a second example,this decoupling can be achieved by releasing the mechanical connectionto one or more of the balloon portions, such as by releasing a clamp onthe balloon portion and/or by cutting the envelope. These envelope cutscan include circumferential cuts (e.g., around the apex fitting), suchas cutting one or more load members (and/or gores, reinforcementelements, etc.) at or near the boundary of the apex fitting.Additionally or alternatively, these cuts can includenon-circumferential cuts, such as cuts directed along (or substantiallyalong) a meridian of the balloon, outward (e.g., radially outward) fromthe apex fitting, and/or in any other suitable directions. For example,this can include cutting one or more reinforcement elements (e.g.,circumferential reinforcement elements), preferably at and/or near theboundary between balloon portions (e.g., as shown in FIG. 5). However,the apex fitting can additionally or alternatively separate the balloonportions from each other in any other suitable manner.

In one example, in which the envelope includes reinforcement elements atand/or near the apex fitting (e.g., circumferential reinforcementelements at the location where the apex fitting couples to theenvelope), splitting the balloon apart (e.g., transitioning to thesecond mode) can include both separating the balloon portions (e.g.,splitting the apex fitting in two pieces, wherein each piece isconnected to a different balloon portion) and cutting the reinforcementelements. The reinforcement elements are preferably cut substantially atthe boundary between balloon portions, but can additionally oralternatively be cut at any other suitable location. Cutting the balloonenvelope (e.g., reinforcement elements) in this manner can includesevering one or more balloon elements entirely, can include partiallycutting one or more balloon elements (e.g., starting a tear from an edgeof the balloon), and/or can include cutting the balloon envelope in anyother suitable manner.

The apex fitting can include one or more actuators configured toseparate the balloon portions (e.g., separate the apex fitting piecesfrom each other, separate balloon portions from the apex fitting, etc.).The separation of balloon portions is preferably achieved withoutcreating sparks and/or introducing other potential sources of ignition(e.g., to avoid igniting hydrogen contained within the balloon).Accordingly, the actuator(s) preferably do not introduce any suchpotential ignition sources; for example, the apex fitting actuator(s)can include one or more wax motors. However, the separation canadditionally or alternatively be achieved in any other suitable manner.

In response to separating the balloon portions at the apex fitting,tensile loads present in the balloon will preferably cause the balloonportions to further separate (e.g., ripping apart from each other,possibly ripping gores and/or separating gores from each other at theseams). Accordingly, the balloon will open (e.g., at or near the apex),and the lighter-than-air fluid contained within will vent from theballoon. However, the apex fitting can additionally or alternativelycause the balloon to open in any other suitable manner.

The apex fitting can optionally include one or more crown valves and/orother elements (e.g., as described in U.S. Provisional PatentApplication 62/969,447, filed 3 Feb. 2020 and titled “Space Capsule”,which is herein incorporated in its entirety by this reference, such asdescribed in U.S. Provisional Patent Application 62/969,447 regardingthe ‘Crown Valve’). Such elements can function to control partialventing of lift gas (e.g., to initiate balloon descent). In one example,the apex fitting includes an attachment portion and a valve portion,such as wherein the attachment portion of the apex fitting attaches to(e.g., seals to) the envelope and surrounds (e.g., circumferentiallysurrounds) the valve portion. However, the valve(s) can additionally oralternatively have any other suitable arrangement within the apexfitting (and/or elsewhere in the balloon), and/or the apex fitting caninclude no such valves.

3.1.3 Nadir Fitting

The balloon can optionally include a nadir fitting 130. The nadirfitting can mechanically couple (e.g., connect) elements of the envelope(e.g., load members, gores, reinforcement elements, etc.) at or near theballoon nadir. The nadir fitting can couple to the envelope in a mannersubstantially analogous to the apex fitting but can additionally oralternatively couple to the envelope in any other suitable manner.

However, the nadir fitting 130 and/or balloon 101 can additionally oralternatively include any other suitable elements in any suitablearrangement.

3.2 Payload

The balloon system can optionally include one or more payloads 102. Thepayload is preferably mechanically connected to the balloon (e.g., by atether, rigid mechanical connection, etc.). The payload is preferablyconnected to the balloon proximal to the balloon nadir (e.g., at thenadir fitting 130). In some examples, this connection can be areleasable connection (e.g., can be operable to transition from aconnected configuration to a released configuration in which themechanical connection between the payload and balloon is separate).

The payload 102 preferably includes a capsule (e.g., for containinghuman passengers), but can additionally or alternatively include anyother suitable elements. In examples, the payload 102 can include one ormore elements such as described in U.S. Provisional Patent Application62/969,447, filed 3 Feb. 2020 and titled “Space Capsule”, which isherein incorporated in its entirety by this reference (e.g., asdescribed in U.S. Provisional Patent Application 62/969,447 regardingthe ‘Capsule System’).

3.3 Safety Module

The system can optionally include one or more safety modules 103, suchas parachutes, auxiliary propulsion systems (e.g., rockets such asretrorockets, propellers, jet engines, etc.), flight control surfaces(e.g., surfaces, such as fixed and/or rotary wings, including rigidwings, parasail wings, and/or any other suitable wings, rudders,ailerons, and/or elevators, configured to control vehicle flight, suchas powered or unpowered descent, in operation as an aerodyne), and/orany other suitable elements. The safety module can function to slowdescent of the system (e.g., in circumstances in which the propulsionmodule is not able to sufficiently slow system descent on its own, incircumstances in which the propulsion module fails and/or is detachedfrom the capsule, etc.), can function to reposition the system (e.g.,redirect capsule trajectory to ensure a water landing rather than aterrestrial landing), and/or can function to provide safety (e.g.,backup safety) for the system in any other suitable manner. The systemcan additionally or alternatively include any other suitable elements(e.g., as described in U.S. Provisional Patent Application 62/969,447,filed 3 Feb. 2020 and titled “Space Capsule”, which is hereinincorporated in its entirety by this reference, such as describedregarding the ‘Backup Descent System’).

However, the balloon system 100 can additionally or alternativelyinclude any other suitable elements in any suitable arrangement.

4. Method

The method 200 for balloon system operation is preferably performedusing the balloon system 100 described above. However, the method 200can additionally or alternatively be performed using any other suitablesystems.

The method 200 can optionally include one or more elements such asdescribed in U.S. Provisional Patent Application 62/969,447, filed 3Feb. 2020 and titled “Space Capsule”, which is herein incorporated inits entirety by this reference. For example, deflating the balloon S230can include one or more elements described in U.S. Provisional PatentApplication 62/969,447 regarding ‘Termination and Deflation’.Additionally or alternatively, operating the balloon system in flightS210 and/or landing the balloon system S220 can include one or moreelements described in U.S. Provisional Patent Application 62/969,447regarding ‘Launch and Recovery’ and/or ‘Buoyancy control’. However, themethod 200 can additionally or alternatively include any other suitableelements described in U.S. Provisional Patent Application 62/969,447.

4.1 Operating the Balloon System in Flight

The method can optionally include operating the balloon system in flightS210. During performance of S210, the balloon is preferably inflatedwith a lighter-than-air fluid (e.g., lift gas, such as hydrogen, helium,etc.). The balloon can be partially inflated, fully or substantiallyfully inflated, and/or have any other suitable inflation state.

S210 can include one or more of: taking off, ascending, maintainingaltitude, maneuvering, descending, and/or any other suitable flightactivities (e.g., as shown in FIG. 7, in which a person of skill in theart will recognize that the balloon system is not shown to scale withchanges in altitude, but rather that the changes in altitude are fargreater than the overall height of the balloon system).

In some embodiments, S210 includes ascending to and/or remaining withina high altitude range. This ascent is made from a lower altitude range,preferably a tropospheric altitude range, such as at or near the Earth'ssurface. In the low altitude range, the balloon is preferably partiallyinflated with the lighter-than-air fluid (e.g., wherein higheratmospheric pressures in this low altitude range prevent expansion ofthe lighter-than-air fluid to fully or substantially fully inflate theballoon). However, the balloon system can additionally or alternativelyascend from any other suitable altitude. In examples, this low altituderange can be less than 0, 0.1, 0.2, 0.5, 1, 2, 5, 7, 10, 15, 20, 25, or30 km above sea level, (e.g., at or substantially at ground level, suchas near sea level or ground level at the site at which the balloonsystem launches and/or lands), but can alternatively be in any othersuitable altitude range.

The high altitude range is preferably a stratospheric altitude range. Inexamples, the high altitude range can be more than 1, 2, 5, 7, 10, 15,20, 25, 30, 35, 40, or 50 km above sea level (e.g., above 30 km or100,000 ft), but can alternatively be in any other suitable altituderange. The balloon preferably inflates during ascent (e.g., due to thereduction in atmospheric air pressure during ascent), and preferablyreaches a fully or substantially fully inflated state at the highaltitude range (e.g., wherein the balloon remains substantially fullyinflated while remaining in the high altitude range).

S210 can include descending from the high altitude range. The descent ispreferably made to a tropospheric altitude range (e.g., less than 0,0.1, 0.2, 0.5, 1, 2, 5, 7, 10, 15, or 20 km above sea level), such as toor near the Earth's surface, but can alternatively be made to a lowerstratospheric altitude (e.g., less than 7, 10, 15, 20, 25, 30, 35, 40,or 50 km above sea level) or to any other suitable altitude. Forexample, the descent can be made in preparation for landing the balloonsystem. During descent, a majority of the lighter-than-air fluid ispreferably retained within the balloon. Despite this retention, theballoon will typically partially deflate during the descent, due to theincrease in atmospheric air pressure.

While operating the balloon system in flight S210, the balloon ispreferably configured in a first mode. In the first mode, the balloon ispreferably partially or fully inflated by the lighter-than-air fluid. Inthe first mode, the balloon portions are preferably mechanicallyconnected to the apex fitting. For example, some or all load members ofthe balloon can be connected (e.g., proximal their respective apex ends)to (and/or by) the apex fitting. In the first mode, the apex fittingpreferably holds the connected balloon portions in tension.

However, S210 can additionally or alternatively include any othersuitable balloon system flight operations in any suitable balloonconfigurations.

4.2 Landing the Balloon System

The method can optionally include landing the balloon system S220, whichcan include controlling the balloon system (e.g., the payload thereof)to contact a landing surface (e.g., land, water, etc.). S220 canoptionally include separating the payload from the balloon (before orafter contacting the landing surface, such as before or after thepayload contacts the landing surface). For example, S220 can includereleasing a tether that mechanically couples the payload to the balloon,thereby releasing the balloon from the payload (e.g., wherein theuntethered balloon will ascend under its reduced weight load).

In some examples, as the payload touches down, its weight is no longerheld by the balloon, but the momentum of the balloon will cause theballoon to continue descending for some time. In these examples, thetether between the payload and balloon is not kept taut following thepayload touchdown, and accordingly, the tension loads within the balloonare typically reduced. Absent a downward force exerted on the balloon bythe payload, the balloon's excess buoyancy will then cause upwardacceleration of the balloon, slowing its descent and then causing it toascend again. In examples in which the balloon is not separated from thepayload, the ascent will stop soon after the balloon ascends far enoughto return tension to the tether (assuming the buoyant force from thelift gas is less than the gravitational force acting on the balloonsystem). Once the balloon's ascent is stopped and the tether is againtaut, the tension loads exerted on the balloon by the tether are onceagain present.

However, S220 can additionally or alternatively include landing theballoon system in any other suitable manner.

4.3 Deflating the Balloon

Deflating the balloon S230 preferably functions to safely vent lift gas(e.g., all or substantially all lift gas) from the balloon. S230preferably includes operating the apex fitting to transition from thefirst mode to a second mode. This transition preferably includesmechanically disconnecting balloon portions from each other (e.g., asdescribed above in more detail, such as regarding the apex fitting 120).In examples, this can include splitting the apex fitting into multiplepieces, disconnecting one or more balloon portions from the apex fitting(e.g., unclamping balloon portions, cutting balloon portions at or neartheir connection to the apex fitting, etc.), and/or mechanicallydisconnecting balloon portions from each other in any other suitablemanner. Optionally, this can additionally or alternatively includecutting the balloon envelope (e.g., reinforcement elements) at or nearone or more boundaries between balloon portions. This preferablyfunctions to create points of weakness (e.g., stress concentrators) atwhich balloon opening can initiate and/or propagate (e.g., wherein theballoon rips apart starting from these points of weakness). Cutting theballoon envelope in this manner can include severing one or more balloonelements (e.g., reinforcement elements) entirely, can include partiallycutting one or more balloon elements (e.g., starting a tear from an edgeof the balloon), and/or can include cutting the balloon envelope in anyother suitable manner.

By operating the apex fitting to transition from the first mode to thesecond mode, the tension held between the balloon portions is preferablyreleased. This can cause the balloon portions to tear apart from eachother (e.g., rip open gores and/or connections between gores, such asconnections sealed by load tapes). Accordingly, the balloon can open atthe apex in response to this apex fitting transition, thereby causingthe lighter-than-air fluid to vent from the opening. However, theballoon deflation can additionally or alternatively be initiated in anyother suitable manner.

In a first embodiment, the balloon deflation is initiated before landing(e.g., before payload touchdown). In this embodiment, the deflation ispreferably initiated while the balloon system is close above the landingsite, but can alternatively be initiated at higher altitude (e.g.,wherein a safety module, such as a parachute, parasail, or other elementis deployed to slow descent of the payload before touchdown).

In a second embodiment, the balloon deflation is initiated after payloadtouchdown. In a first variation of this embodiment, it is initiatedduring the low-balloon tension period just after touchdown (e.g., whenthe tether between the payload and balloon is not taut). In a secondvariation, balloon deflation is initiated after tension returns to thetether, preferably at a time at which the balloon is displaced laterallyfrom the payload such that it is not directly above the payload (e.g., aprojection of the balloon along the gravity vector does not intersectthe payload, is farther than a threshold distance from the payload suchas more than 5, 10, 15, 20, 30, 50, 70, 100, 200, 300, or 500 m away,etc.). This lateral displacement preferably occurs due to wind forcesacting on the balloon (e.g., wherein S230 includes waiting until winddisplaces the balloon laterally from the payload before controlling thesystem to initiate balloon deflation). However, the displacement canadditionally or alternatively be achieved by one or more lateralpropulsion modules (e.g., lateral propulsion module of the payloadand/or balloon).

However, S230 can additionally or alternatively be performed with anyother suitable timing. Further, the method 200 can additionally oralternatively include operating the balloon system in any other suitablemanner.

An alternative embodiment preferably implements the some or all of abovemethods in a computer-readable medium storing computer-readableinstructions. The instructions are preferably executed bycomputer-executable components preferably integrated with acommunication routing system. The communication routing system mayinclude a communication system, routing system and a pricing system. Thecomputer-readable medium may be stored on any suitable computer readablemedia such as RAMs, ROMs, flash memory, EEPROMs, optical devices (CD orDVD), hard drives, floppy drives, or any suitable device. Thecomputer-executable component is preferably a processor but theinstructions may alternatively or additionally be executed by anysuitable dedicated hardware device.

Although omitted for conciseness, embodiments of the system and/ormethod can include every combination and permutation of the varioussystem components and the various method processes, wherein one or moreinstances of the method and/or processes described herein can beperformed asynchronously (e.g., sequentially), concurrently (e.g., inparallel), or in any other suitable order by and/or using one or moreinstances of the systems, elements, and/or entities described herein.

The FIGURES illustrate the architecture, functionality and operation ofpossible implementations of systems, methods and computer programproducts according to preferred embodiments, example configurations, andvariations thereof. In this regard, each block in the flowchart or blockdiagrams may represent a module, segment, step, or portion of code,which comprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that, in somealternative implementations, the functions noted in the block can occurout of the order noted in the FIGURES. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts, or combinations of special purpose hardware andcomputer instructions.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the preferred embodiments of the invention withoutdeparting from the scope of this invention defined in the followingclaims.

I claim:
 1. A method for operating a balloon system comprising a balloonand a payload mechanically connected to the balloon, the methodcomprising, at the balloon system: while a lighter-than-air fluid iscontained within the balloon, descending from an Earth stratosphere toan Earth troposphere, thereby partially deflating the balloon, whereinthe balloon comprises: an apex fitting arranged at an apex of theballoon, the apex fitting comprising a first portion and a secondportion; a first balloon portion mechanically connected to the firstportion of the apex fitting; and a second balloon portion mechanicallyconnected to the first balloon portion via the second portion of theapex fitting, wherein the apex fitting maintains a tension between thefirst and second balloon portions; and while in the Earth troposphere,while the balloon is partially deflated, at the apex fitting,mechanically disconnecting the first portion of the apex fitting fromthe second portion of the apex fitting, thereby releasing the tensionbetween the first and second balloon portions and mechanicallydisconnecting the first balloon portion from the second balloon portion,wherein, in response to mechanically disconnecting the first balloonportion from the second balloon portion, the balloon opens and thelighter-than-air fluid vents from the balloon.
 2. The method of claim 1,wherein descending from the Earth stratosphere to the Earth tropospherecomprises landing the payload such that the payload is at leastpartially supported by a surface of the Earth, wherein mechanicallydisconnecting the first balloon portion from the second balloon portionis performed while the payload is at least partially supported by thesurface.
 3. The method of claim 2, wherein the surface is a surface of abody of water.
 4. The method of claim 2, wherein: while the balloonsystem is in the Earth stratosphere, a mechanical connection between thepayload and the balloon is under a first tension; after landing thepayload, the mechanical connection is under reduced tension as comparedwith the first tension; and mechanically disconnecting the first balloonportion from the second balloon portion is performed while themechanical connection is under reduced tension.
 5. The method of claim2, wherein mechanically disconnecting the first balloon portion from thesecond balloon portion is performed while a projection of the balloonalong a gravity vector does not intersect the payload.
 6. The method ofclaim 1, further comprising, while in the Earth troposphere, beforemechanically disconnecting the first balloon portion from the secondballoon portion, mechanically uncoupling the payload from the balloon.7. The method of claim 1, further comprising, at the balloon system,while the lighter-than-air fluid is contained within the balloon, beforedescending from the Earth stratosphere to the Earth troposphere,ascending from the Earth troposphere to the Earth stratosphere.
 8. Themethod of claim 1, wherein, while the balloon system is in the Earthstratosphere, the balloon is substantially fully inflated.
 9. The methodof claim 1, wherein: while in the Earth stratosphere, the balloondefines a first volume; and while in the Earth troposphere, afterdescending to the Earth troposphere and before mechanicallydisconnecting the first balloon portion from the second balloon portion,the balloon defines a second volume, wherein the first volume is greaterthan the second volume by a factor greater than
 10. 10. The method ofclaim 1, wherein the lighter-than-air fluid comprises molecular hydrogengas.
 11. The method of claim 1, wherein: the first balloon portioncomprises a first plurality of gores; and the second balloon portioncomprises a second plurality of gores.
 12. The method of claim 11,wherein: the balloon defines a central axis between the apex and a nadirof the balloon; the balloon further comprises a reinforcement portionencircling the central axis, wherein the first and second balloonportions are mechanically connected to the apex fitting via thereinforcement portion; and mechanically disconnecting the first balloonportion from the second balloon portion comprises: at the apex fitting,releasing at least one of the first balloon portion or the secondballoon portion; and cutting the reinforcement portion proximal aboundary between the first and second balloon portions.
 13. A balloonsystem comprising a balloon configured to contain a lighter-than-airfluid, the balloon comprising: a plurality of gores substantiallydefining a balloon envelope; a plurality of load members comprising afirst set of load members and a second set of load members; and an apexfitting arranged at a balloon apex, the apex fitting comprising a firstapex member attached to the first set of load members and a second apexmember attached to the second set of load members; wherein: the firstand second sets of load members are disjoint; each load member of theplurality defines an apex end and a nadir end opposing the apex endalong a length of the load member; each load member of the pluralitymechanically connects a respective pair of adjacent gores along a lengthof the gores; in a first mode, the balloon is partially inflated by thelighter-than-air fluid and each load member of the plurality ismechanically connected to the apex fitting proximal the apex end of theload member, thereby holding each load member of the plurality intension; in the first mode, the first apex member is mechanicallyconnected to the second apex member; the apex fitting is operable totransition the balloon from the first mode to a second mode bymechanically disconnecting the first set of load members from the secondset of load members, the apex fitting is operable to mechanicallydecouple the first set of load members from the second set of loadmembers by detaching the first apex member from the second apex member,wherein, in response to mechanically disconnecting the first set of loadmembers from the second set of load members, the balloon opens and thelighter-than-air fluid vents from the balloon.
 14. The balloon system ofclaim 13, wherein: the plurality of load members further comprises athird set of load members disjoint from the first and second sets ofload members; the apex fitting further comprises a third apex memberattached to the third set of load members; in the first mode, the thirdapex member is mechanically connected to the first apex member; andtransitioning the balloon from the first mode to the second mode furthercomprises mechanically decoupling the third set of load members from thefirst and second sets of load members, comprising detaching the firstapex member from the third apex member.
 15. The balloon system of claim13, wherein the apex fitting further comprises a wax motor operable todetach the first apex member from the second apex member.
 16. Theballoon system of claim 13, wherein: the balloon defines a central axisbetween the balloon apex and a balloon nadir; the balloon furthercomprises a reinforcement portion encircling the central axis, whereineach load member of the plurality is mechanically connected to the apexfitting via the reinforcement portion; the apex fitting comprises ablade; and transitioning the balloon from the first mode to the secondmode comprises cutting the reinforcement portion proximal a boundarybetween the first and second sets of load members.
 17. The balloonsystem of claim 13, wherein the gores comprise a polymer film.
 18. Theballoon system of claim 13, wherein the balloon is a zero-pressureballoon.
 19. The balloon system of claim 13, further comprising apayload tethered to the balloon.
 20. A method for operating a balloonsystem comprising a balloon and a payload mechanically connected to theballoon, the method comprising, at the balloon system: while alighter-than-air fluid is contained within the balloon, descending froman Earth stratosphere to an Earth troposphere, thereby partiallydeflating the balloon, wherein descending from the Earth stratosphere tothe Earth troposphere comprises landing the payload such that thepayload is at least partially supported by a surface of the Earth,wherein the balloon comprises: an apex fitting arranged at an apex ofthe balloon; a first balloon portion mechanically connected to the apexfitting; and a second balloon portion mechanically connected to thefirst balloon portion via the apex fitting, wherein the apex fittingmaintains a tension between the first and second balloon portions; andwhile in the Earth troposphere, while the balloon is partially deflated,at the apex fitting, mechanically disconnecting the first balloonportion from the second balloon portion, thereby releasing the tensionbetween the first and second balloon portions, wherein, in response tomechanically disconnecting the first balloon portion from the secondballoon portion, the balloon opens and the lighter-than-air fluid ventsfrom the balloon, wherein mechanically disconnecting the first balloonportion from the second balloon portion is performed while the payloadis at least partially supported by the surface.
 21. The method of claim20, wherein the surface is a surface of a body of water.
 22. The methodof claim 20, wherein: while the balloon system is in the Earthstratosphere, a mechanical connection between the payload and theballoon is under a first tension; after landing the payload, themechanical connection is under reduced tension as compared with thefirst tension; and mechanically disconnecting the first balloon portionfrom the second balloon portion is performed while the mechanicalconnection is under reduced tension.
 23. The method of claim 20, whereinmechanically disconnecting the first balloon portion from the secondballoon portion is performed while a projection of the balloon along agravity vector does not intersect the payload.